Make pr check available for markdownlint 📝 (#1446)

* Make pr check available for markdownlint (hopefully).
Signed-off-by: Jerome Luckenbach <github@luckenba.ch>

.github/workflows/markdownlint.yml

@@ -1,14 +1,8 @@
 name: Checking Markdown For Errors
 
-on:
-  pull_request:
-    branches:
-      - main
-    types:
-      - open
-      - synchronize
-      - reopen
+# https://github.blog/2020-08-03-github-actions-improvements-for-fork-and-pull-request-workflows/
 
+on:
   push:
     branches:
       - main
@@ -16,6 +10,14 @@ on:
     tags-ignore:
       - '**'
 
+  pull_request_target:
+    branches:
+      - main
+    types:
+      - open
+      - synchronize
+      - reopen
+
 jobs:
   markdownlint:
     runs-on: ubuntu-latest